Heyers et al.
A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds.
Dominik Heyers mail, Martina Manns, Harald Luksch, Onur Güntürkün, Henrik Mouritsen
Published: September 26, 2007 DOI: 10.1371/journal.pone.0000937
Citation: Heyers D, Manns M, Luksch H, Güntürkün O, Mouritsen H (2007) A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds. PLoS ONE 2(9): e937. doi:10.1371/journal.pone.0000937
Academic Editor: Andrew Iwaniuk, University of Alberta, Canada
Received: April 10, 2007; Accepted: September 5, 2007; Published: September 26, 2007
Copyright: © 2007 Heyers et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: VolkswagenStiftung (“Dynamics and adaptivity of neuronal systems” grant given to D. Heyers and “Nachwuchsgruppe/Lichtenberg” grant given to H. Mouritsen), Deutsche Forschungsgemeinschaft (FOR 701 and MO 1408/1-2 grants to H. Mouritsen; Lu 622/8 grant to H. Luksch; SFB 509 to M. Manns and O. Güntürkün).
Competing interests: The authors have declared that no competing interests exist.
The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, “Cluster N”, show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds “see” the reference compass direction provided by the geomagnetic field.